ACIDS OCCURRING IN FATS 



^^3>CH CH,,CH.,COOH or C,.,Hi„0. Isobutyl acetic or caproic acid 



It should be noted that these acids all conform to the 

 general formula for the fatty acids, CnH2nO^, in which " n " may 

 have any value, odd or even, but only those in which " n " is an 

 even number are found to occur naturally in fats ; the alleged 

 occurrence in natural fats of acids with an uneven number of 

 carbon atoms has in every case, so far recorded, been refuted on 

 careful re-examination. 



It appears probable, moreover, that all naturally occurring 

 fatty acids have a straight and not a branched carbon chain, 

 so that it is open to question whether the zj^-butyl acetic acid 

 which is said to have been found in fats was not, in reality, 

 normal caproic acid of the formula CH3(CH2)4COOH, 



Besides acids of the fatty series whose general formula is 

 CnH^nOg, acids belonging to several other series, poorer in 

 hydrogen than the above, are found in fats. The simplest 

 example of such a series of acids is furnished by the acids of 

 the Oleic series, the members of which differ from the corre- 

 sponding members of the fatty acid series in having two atoms 

 of hydrogen less. 



Some of the more important acids of this group are given 

 below. 



I. Acids of the OLEIC or AcRYLIC series. 

 General formula CnH.^n-sO^. 



CsHgOa Tiglic acid 



CjsHg^Oa Oleic acid 



C18H34O2 Elaidic acid 



CjgHjjOg Iso-oleic acid 



Ca^HjaOj Erucic acid 



C22H42O2 Brassidic acid 



The most widely distributed of these acids is undoubtedly 

 oleic acid, which, in the form of its glyceride triolein, 



